| From: | Andrew Dunstan <andrew(at)dunslane(dot)net> |
|---|---|
| To: | Greg Smith <gsmith(at)gregsmith(dot)com>, Emmanuel Cecchet <manu(at)asterdata(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, Emmanuel Cecchet <Emmanuel(dot)Cecchet(at)asterdata(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: generic copy options |
| Date: | 2009-09-17 23:45:45 |
| Message-ID: | 4AB2CA29.3060206@dunslane.net |
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| Lists: | pgsql-hackers |
Dan Colish wrote:
> CREATE TABLE
> INSERT 0 100000
> Timing is on.
> COPY 100000
> Time: 83.273 ms
> BEGIN
> Time: 0.412 ms
> TRUNCATE TABLE
> Time: 0.357 ms
> COPY 100000
> Time: 140.911 ms
> COMMIT
> Time: 4.909 ms
>
>
>
Anything that doesn't have times that are orders of magnitude greater
than this is pretty much useless as a measurement of COPY performance,
IMNSHO.
In this particular test, to check for paring times, I'd be inclined to
do copy repeatedly (i.e. probably quite a few thousand times) from an
empty file to test the speed. Something like:
select current_timestamp;
begin;
truncate;
copy;copy;copy; ...
commit;
select current_timestamp;
(tests like this are really a good case for DO ' something'; - we could
put a loop in the DO.)
cheers
andrew
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